A common problem in domestic water heating systems (hereinafter also referred to as “boiler systems”) is the accumulation of limescale, due to minerals, such as calcium and magnesium, that exist within the within the water. The term “Hard water” typically refers to water which contains a relatively high concentration of dissolved minerals, and such “hard water” is often used in relation to domestic water heating systems.
The presence of hard water in water tanks of domestic water heating system leaves precipitations, like calcium carbonate on the surface it is in contact with. Said calcium carbonate precipitation often builds up and can cause significant problems. For instance, water pipes diameter might be reduced; the shape of components might be distorted and heating elements become less efficient. As a result, in an environment of hard water, domestic water heating systems require relatively frequent maintenance which involves replacement of pipes, heating elements and other water components.
The accumulation of limescale increases as the temperature of the water changes repeatedly. Another cause for an increased accumulation of limescale is a lack of water flow. In still (i.e., non-flowing) water the minerals are free to sink down to the surface with no interference. In domestic water heating systems both conditions exist, since the water within the container are still most of the time, and flow is obtained only when a user opens a tap to consume hot water from the boiler. Obviously the second condition also applies each time the heater of a boiler is turned on where the water is heated to a relatively high temperature and then cools down to outdoor temperature.
Heating elements of domestic water heating systems are typically enclosed within a sleeve-shaped cover, which contributes to the efficiency of the system, since it creates a smaller-volume tank of water within the large tank, thus the water is heated faster and is ready for domestic use. A drawback of the use of such a cover is the fact that the encasing of the heating element within a sleeve substantially reduces the free flow of water, a reduction which in turn increases the formation of precipitation.
The accumulation of limescale around a heating element reduces the heat transfer from the element to the water, since the limescale somewhat insulates the heating element from the water. The reduction of the heat transfer leads to a higher consumption of electricity in order to reach a desired water temperature. Moreover, the heating element is more likely to be damaged in an environment of high precipitations, and it is also more likely that different components of domestic water heating systems will have to be replaced when the precipitation reaches a certain degree. The need for additional electric power and the need for frequent replacement of components is time consuming, not to mention financial expenses.
One solution available today for the accumulation of limescale involves the use of chemicals that soften hard water by changing their chemical composition. Such chemicals that are suitable for domestic use typically provide water that consist sodium or potassium instead of calcium and magnesium. This solution is problematic as in that case the softened water has high concentration of salt and it lacks the valuable minerals, namely calcium and magnesium. Water with high concentration of salt may be unsafe for domestic uses such as drinking, cooking, plant irrigation and so on. Moreover, the water flow through the sewerage system or the ground may cause contamination of water resources and damage to the environment. Other chemical solutions involve using phosphates, zinc, arsenic and other heavy metals. The most common method which is known in the prior art is the use of Phosphate Siliphos beans that in fact comprises the chemical formula of P2O5 phosphoric acid. This process replaces the minerals, and prevents the formation of limescale. However, new studies indicate unequivocally that the existence of arsenic in water causes abortion in pregnant women and is a significant factor for a cancer disease.
The prior art also suggested the use of a magnetic field for the removal of precipitations. Another prior art method suggests the creation of an electrical field, which is unsafe and requires massive maintenance.
In addition, according to the prior art, the inlet of cold-water to the boiler is typically located at the side of the sleeve (“accelerator”). The sleeve is designed to have an aperture to allow water to flow in. Nevertheless, once the sleeve is full of water and at times of heating, said aperture causes heat loss and decrease the efficiency of the heating.
Therefore, it is an object of the present invention to provide a system and method for decreasing the formation of precipitations in water heating systems, particularly in boilers.
It is another object of the invention to provide a system and a method that decreases the heat loss in domestic water heating systems.
Other objects and advantages of the invention will become apparent as the description proceeds.